Browsing by Author "Muehlleitner, Margarete"
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- 2HDM Higgs-to-Higgs decays at next-to-leading orderPublication . Krause, Marcel; Muehlleitner, Margarete; Santos, Rui; Ziesche, HannaThe detailed investigation of the Higgs sector at present and future colliders necessitates from the theory side as precise predictions as possible, including higher-order corrections. An important ingredient for the computation of higher-order corrections is the renormalization of the model parameters and fields. In this paper we complete the renormalization of the two-Higgs-doublet model (2HDM) Higgs sector launched in a previous contribution with the investigation of the renormalization of the mixing angles alpha and beta. Here, we treat the renormalization of the mass parameter m(12)(2) that softly breaks the Z(2) symmetry of the 2HDM Higgs sector. We investigate the impact of two different renormalization schemes on the sample Higgs-to-Higgs decay H -> hh. This decay also allows us to analyze the renormalization of the mixing angles and to confirm the properties extracted before in other Higgs decays. In conclusion we find that a gauge-independent, process-independent and numerically stable renormalization of the 2HDM Higgs sector is given by the application of the tadpole-pinched scheme for the mixing angles a and beta and by the use of the modified minimal subtraction scheme for m(12)(2).
- Electroweak corrections in a pseudo Nambu-Goldstone Dark Matter model revisitedPublication . Glaus, Seraina; Muehlleitner, Margarete; Mueller, Jonas; Patel, Shruti; Roemer, Tizian; Santos, RuiHaving so far only indirect evidence for the existence of Dark Matter a plethora of experiments aims at direct detection of Dark Matter through the scattering of Dark Matter particles off atomic nuclei. For the correct interpretation and identification of the underlying nature of the Dark Matter constituents higher-order corrections to the cross section of Dark Matter-nucleon scattering are important, in particular in models where the tree-level cross section is negligibly small. In this work we revisit the electroweak corrections to the dark matter-nucleon scattering cross section in a model with a pseudo Nambu-Goldstone boson as the Dark Matter candidate. Two calculations that already exist in the literature, apply different approaches resulting in different final results for the cross section in some regions of the parameter space leading us to redo the calculation and analyse the two approaches to clarify the situation. We furthermore update the experimental constraints and examine the regions of the parameter space where the cross section is above the neutrino floor but which can only be probed in the far future.
- LHC dark matter working group: next-generation spin-0 dark matter modelsPublication . Abe, Tomohiro; Afik, Yoav; Albert, Andreas; Anelli, Christopher R.; Barak, Liron; Bauer, Martin; Behr, J. Katharina; Bell, Nicole; Boveia, Antonio; Brandt, Oleg; Busoni, Giorgio; Carpenter, Linda M.; Chen, Yu-Heng; Doglioni, Caterina; Elliot, Alison; Fujiwara, Motoko; Genest, Marie-Helene; Gerosa, Raffaele; Gori, Stefania; Gramling, Johanna; Grohsjean, Alexander; Gustavino, Giuliano; Hahn, Kristian; Haisch, Ulrich; Henkelmann, Lars; Hisano, Junji; Huitfeldt, Anders; Ippolito, Valerio; Kahlhoefer, Felix; Landsberg, Greg; Lowette, Steven; Maier, Benedikt; Maltoni, Fabio; Muehlleitner, Margarete; No, Jose M.; Pani, Priscilla; Polesello, Giacomo; Price, Darren D.; Robens, Tania; Rovelli, Giulia; Rozen, Yoram; Sanderson, Isaac W.; Santos, Rui; Sevova, Stanislava; Sperka, David; Sung, Kevin; Tait, Tim M. P.; Terashi, Koji; Ungaro, Francesca; Vryonidou, Eleni; YU, SHIN-SHAN; Wu, Sau Lan; Zhou, ChenDark matter (DM) simplified models are by now commonly used by the ATLAS and CMS Collaborations to interpret searches for missing transverse energy (E-T(miss)). The coherent use of these models sharpened the LHC DM search program, especially in the presentation of its results and their comparison to DM direct-detection (DD) and indirect-detection (ID) experiments. However, the community has been aware of the limitations of the DM simplified models, in particular the lack of theoretical consistency of some of them and their restricted phenomenology leading to the relevance of only a small subset of E-T(miss) signatures. This document from the LHC Dark Matter Working Group identifies an example of a next-generation DM model, called 2HDM+a, that provides the simplest theoretically consistent extension of the DM pseudoscalar simplified model. A comprehensive study of the phenomenology of the 2HDM+a model is presented, including a discussion of the rich and intricate pattern of mono-X signatures and the relevance of other DM as well as non-DM experiments. Based on our discussions, a set of recommended scans are proposed to explore the parameter space of the 2HDM+a model through LHC searches. The exclusion limits obtained from the proposed scans can be consistently compared to the constraints on the 2HDM+a model that derive from DD, ID and the DM relic density.
- Phenomenological comparison of models with extended Higgs sectorsPublication . Muehlleitner, Margarete; Sampaio, Marco O. P.; Santos, Rui; Wittbrodt, JonasBeyond the Standard Model (SM) extensions usually include extended Higgs sectors. Models with singlet or doublet fields are the simplest ones that are compatible with the rho parameter constraint. The discovery of new non-SM Higgs bosons and the identification of the underlying model requires dedicated Higgs properties analyses. In this paper, we compare several Higgs sectors featuring 3 CP-even neutral Higgs bosons that are also motivated by their simplicity and their ability to solve some of the flaws of the SM. They are: the SM extended by a complex singlet field (CxSM), the singlet extension of the 2-Higgs-Doublet Model (N2HDM), and the Next-to-Minimal Supersymmetric SM extension (NMSSM). In addition, we analyse the CP-violating 2-Higgs-Doublet Model (C2HDM), which provides 3 neutral Higgs bosons with a pseudoscalar admixture. This allows us to compare the effects of singlet and pseudoscalar admixtures. Through dedicated scans of the allowed parameter space of the models, we analyse the phenomenologically viable scenarios from the view point of the SM-like Higgs boson and of the signal rates of the non-SM-like Higgs bosons to be found. In particular, we analyse the effect of singlet/pseudoscalar admixture, and the potential to differentiate these models in the near future. This is supported by a study of couplings sums of the Higgs bosons to massive gauge bosons and to fermions, where we identify features that allow us to distinguish the models, in particular when only part of the Higgs spectrum is discovered. Our results can be taken as guidelines for future LHC data analyses, by the ATLAS and CMS experiments, to identify specific benchmark points aimed at revealing the underlying model.
- Phenomenological comparison of models with extended Higgs sectorsPublication . Muehlleitner, Margarete; Sampaio, Marco O. P.; Santos, Rui; Wittbrodt, JonasBeyond the Standard Model (SM) extensions usually include extended Higgs sectors. Models with singlet or doublet fields are the simplest ones that are compatible with the rho parameter constraint. The discovery of new non-SM Higgs bosons and the identification of the underlying model requires dedicated Higgs properties analyses. In this paper, we compare several Higgs sectors featuring 3 CP-even neutral Higgs bosons that are also motivated by their simplicity and their ability to solve some of the flaws of the SM. They are: the SM extended by a complex singlet field (CxSM), the singlet extension of the 2-Higgs-Doublet Model (N2HDM), and the Next-to-Minimal Supersymmetric SM extension (NMSSM). In addition, we analyse the CP-violating 2-Higgs-Doublet Model (C2HDM), which provides 3 neutral Higgs bosons with a pseudoscalar admixture. This allows us to compare the effects of singlet and pseudoscalar admixtures. Through dedicated scans of the allowed parameter space of the models, we analyse the phenomenologically viable scenarios from the view point of the SM-like Higgs boson and of the signal rates of the non-SM-like Higgs bosons to be found. In particular, we analyse the effect of singlet/pseudoscalar admixture, and the potential to differentiate these models in the near future. This is supported by a study of couplings sums of the Higgs bosons to massive gauge bosons and to fermions, where we identify features that allow us to distinguish the models, in particular when only part of the Higgs spectrum is discovered. Our results can be taken as guidelines for future LHC data analyses, by the ATLAS and CMS experiments, to identify specific benchmark points aimed at revealing the underlying model.